Container systems are used in many industries for storing, shipping and/or dispensing materials of a variety of viscosities. For example, numerous manufacturing processes require the use of ultrapure liquids, such as acids, solvents, bases, photoresists, slurries, cleaning formulations, dopants, inorganic, organic, metalorganic and biological solutions, pharmaceuticals, and radioactive chemicals. Such applications require that the number and size of particles in the ultrapure liquids be minimized. In particular, because ultrapure liquids are used in many aspects of the microelectronic manufacturing process, semiconductor manufacturers have established strict particle concentration specifications for process chemicals and chemical-handling equipment. Such specifications are needed because, should the liquids used during the manufacturing process contain sufficient levels of particles or bubbles, the particles or bubbles may be deposited on solid surfaces of the silicon. This can, in turn, lead to product failure or reduced quality and reliability. In some cases the contents of a container may be expensive and, as such, defects in an end process, such as a semiconductor process, resulting from contamination of the liquid stored in the container system can have significant adverse and costly consequences.
To help protect the contents of such containers, often, at a mouth or other opening to such containers, a protective seal may be provided to, for example, seal in the contents of the container and prevent contaminants or light from being introduced into the container and thus into the material stored therein. The seal can be a rupturable seal or membrane, or what is commonly referred to as a “breakseal.” A breakseal is typically designed such that the breakseal does not rupture or break by impact or pressures commonly occurring, for example, during transport and handling of the container, but easily ruptures when punctured by a force applied, for example, by a dispense system connector for dispensing the contents of the container.
Breakseals also protect operating personnel. A tear tab is typically removed with the breakseal in place. After removal of the tear tab, the breakseal is ruptured with a probe for coupling to a bottle and tool. The breakseal prevents caustic liquids from entering the breakseal cavity so as not to harm or injure operating personnel who remove the tear tab. The breakseal also protects operating personnel from spilling, splashes, and vapor during the coupling with the tool.
Certain deficiencies in breakseals of the prior art have been discovered. Such deficiencies include “shedding” of foam utilized in two-layered structures. In two-layered breakseal structures, a first layer of laminated low-density polyethylene (LDPE) foam and a second layer of polytetrafluoroethylene (PTFE) film are bonded together using an adhesive. In a central portion of the breakseal, tear lines or score lines extend radially from the center, such that when a dispense system connector is pressed against the breakseal for connection with the container, the tear lines permit the breakseal to tear. The LDPE foam and use of adhesives in such breakseals can lead to undesirable contamination because of “shedding” of the foam (i.e., generation of particulates when subject to friction). Downstream defects can thereby result in certain manufacturing processes. Furthermore, the adhesive material used to bond the two layers may be introduced into the material stored within the storage container, thereby reducing the purity of the material and causing problems in downstream processes.
There is a need for a breakseals which reduce and/or minimize contamination of contents in a container system. Particularly, there is a need for breakseals and methods of making the breakseals for use in shipping and dispensing systems, such as those typically used for the storage, transport, and dispense of photosensitive reagents or other ultrapure chemicals used in the semiconductor manufacturing industry. The present disclosure relates to breakseal embodiments which can overcome the disadvantages of traditional breakseals, and describes breakseal embodiments that can be produced with relatively low cost and by processes that are simpler than traditional breakseals and/or that enhance prevention of contamination to the contents of a container system.